VIIRS Science Quality L2
Ocean color data from the VIIRS sensor aboard the S-NPP satellite are provided as a global life-of-mission science quality collection starting from November 2011.
Data are available through:
- anonymous FTP and
- THREDDS
Datasets can be previewed and downloaded using the VIIRS Granule Selector.
Data are processed using NOAA MSL12 ocean color data processing system (SCI_OC03_V1.10). This science quality collection differs from the S-NPP-VIIRS near real time products in several ways:
| Science Quality | Near real-time | |
|---|---|---|
| Latency | Delayed 2 weeks | ~12 hours (best effort) |
| Sensor Data Record(SDR) | Ocean Color improved SDR | IDPS Operational SDR |
| Ancillary Data | Assimilated | Predicted |
| Spatial Coverage | Complete | May have gaps |
Standard S-NPP-VIIRS data products include:
- Normalized water-leaving (nLw)radiance at five visible bands (nominal center wavelengths)
- M1 (410nm)
- M2 (443nm)
- M3 (486nm)
- M4 (551nm)
- M5 (671nm)
- Chlorophyll-a concentration
- Diffuse attenuation coefficient at 490nm(Kd490), and
- Diffuse attenuation coefficient of the photosynthetically available radiation (KdPAR)
Additional metadata can be obtained using THREDDS services such as ISO or OPeNDAP.
Level-2 products are organized by Year and Day-of-the-Year. Filenames will appear as follows: V2011355013534_NPP_SCINIR_L2.nc where:
- V: Sensor VIIRS
- 2011: Year of observation
- 355: Day of year for the observation
- 013534: Hour, minutes, and seconds of the start of observation (hhmmss) in UTC
- NPP: Spacecraft S-NPP
- SCINIR: Sensor data record source and environmental data record algorithm. SCI = ocean color SDR and NIR = near-infrared
- L2: Processing level. L2 includes calibrated and geolocated geophysical products
Data files are in NetCDF4/CF but differ from past NOAA CoastWatch products in their use of hierarchical groups to store attributes, variables, and dimensions.
The CoastWatch Software has been updated to work with these files.
